A Freshwater Clam (Corbicula fluminea) Extract Improves Cholesterol Metabolism in Rats Fed on a High-Cholesterol Diet

The effect of a freshwater clam (Corbicula fluminea) extract (FCE) on cholesterol metabolism in rats fed on a high-cholesterol diet was investigated. When rats were fed various amounts of FCE in addition to the high-cholesterol diet for 2 wk, the serum and hepatic cholesterol levels were gradually reduced in a dose-dependent manner, as compared with the control group. The excretion of neutral sterols and bile acids into the feces was increased by feeding FCE. Several phytosterols were detected in the feces of rats fed on the FCE-containing diet. In addition, substantial amounts of phytosterols were found in FCE. Cholesterol 7α-hydroxylase (CYP7A1) mRNA in the liver of the rats fed on the FCE-containing diets was higher than that of rats fed on the high-cholesterol diets without FCE. These results may suggest that enhanced cholesterol degradation and the excretion of neutral sterols and bile acids contributed to the hypocholesterolemic effect of FCE observed in the hypercholesterolemic rats fed on the high-cholesterol diet.     

Effect of dietary inclusion of Lactobacillus acidophilus ATCC 43121 on cholesterol metabolism in rats

This study examined the effects of Lactobacillus acidophilus ATCC 43121 (LAB) on cholesterol metabolism in hypercholesterolemia-induced rats. Four treatment groups of rats (n = 9) were fed experimental diets: normal diet, normal diet+LAB (2 x 10(6) CFU/day), hypercholesterol diet (0.5% cholesterol, w/w), and hypercholesterol diet + LAB. Body weight, feed intake, and feed efficiency did not differ among the four groups. Supplementation with LAB reduced total serum cholesterol (25%) and VLDL + IDL + LDL cholesterol (42%) in hypercholesterol diet groups, although hepatic tissue cholesterol and lipid contents were not changed. In the normal diet group, cholesterol synthesis (HMG-CoA reductase expression), absorption (LDL receptor expression), and excretion via bile acids (cholesterol 7 alpha-hydroxylase expression) were increased by supplementation with LAB, and increased cholesterol absorption and decreased excretion were found in the hypercholesterol diet group. Total fecal acid sterols excretion was increased by supplementation with LAB. With proportional changes in both normal and hypercholesterol diet groups, primary bile acids (cholic and chenodeoxycholic acids) were reduced, and secondary bile acids (deoxycholic and lithocholic acids) were increased. Fecal neutral sterol excretion was not changed by LAB. In this experiment, the increase in insoluble bile acid (lithocholic acid) reduced blood cholesterol level in rats fed hypercholesterol diets supplemented with LAB. Thus, in the rat, L. acidophilus ATCC 43121 is more likely to affect deconjugation and dehydroxylation during cholesterol metabolism than the assimilation of cholesterol into cell membranes.     

Steroid balance and tissue cholesterol accumulation in germfree and conventional rats fed diets containing saturated and polyunsaturated fats

Steroid balance studies were conducted on 24 conventional and 12 germfree male rats, 90-120 days old, fed diets containing either 20% safflower or 20% coconut oil. Both germfree and conventional rats fed the safflower oil diets had significantly lower serum cholesterol levels and significantly higher liver cholesterol levels than did the rats fed coconut oil. No significant differences in total fecal neutral sterols, coprostanol, Delta(7)-cholestenol, or total fecal bile acid excretion were seen between dietary groups of rats of either status. There was no evidence of qualitative differences in fecal bile acid excretion as a function of diet. The increased liver cholesterol was in the ester form, with cholesteryl linoleate the largest single component. There was no significant difference in the cholesterol content of the skin, muscle, adipose tissue, or gastrointestinal tract. The significance of a large increase in liver cholesteryl ester, lowered serum cholesterol, and no change in steroid excretion is discussed.     

Fecal neutral steroids and bile acids from germfree rats

The amount and composition of fecal neutral sterols and bile acids excreted by adult male germfree and conventional rats have been determined. The amounts of neutral sterols excreted were 12.8 (germfree) and 19.5 (conventional) mg/kg of body wt per day. The germfree rats excreted cholesterol and lathosterol (methostenol was not assayed); the conventional rats excreted coprostanol and coprostanone in addition. The amounts of bile acids excreted were 11.3 (germfree) and 21.4 (conventional) mg/kg of body wt per day. The bile acids excreted by the rats were tentatively identified as tauro--muricholate, tauro-alpha-muricholate, and tauro-cholate, besides an unidentified component. The conventional rats excreted the corresponding unconjugated acids as well as many other unconjugated bile acids. No significant correlation was found between the amount of coprosterols and the total amount of neutral sterols excreted by the conventional rats. This suggests that bacterial reduction of cholesterol is not an important mechanism of increasing neutral sterol excretion of conventional rats as compared to germfree rats. Evidence is presented that suggests that this difference in neutral sterol excretion is due to changes in intestinal secretion and sloughing between the two types of animal. The factors reponsible for the differences in bile acid excretion have not been identified.     

Effect of diosgenin on lipid metabolism in rats.

The purpose of this study was to determine whether diosgenin suppresses cholesterol absorption in rats, and to examine relevant changes in cholesterol and bile acid metabolism. Diosgenin fed with the diet for 1 week inhibited cholesterol absorption as determined by the serum isotope ratio technique, as well as by measuring in the feces the amount of unabsorbed radioactivity from orally administered [3H]cholesterol. In addition, diosgenin suppressed the serum and liver uptake of radioactivity from co-administered [3H]cholesterol as well as the accumulation of liver cholesterol in the cholesterol-fed rat; diosgenin was substantially more active than cholestyramine or beta-sitosterol. In vitro, diosgenin had no effect on the activity of rat pancreatic esterase. Diosgenin decreased the elevated cholesterol in serum LDL and elevated cholesterol in the HDL fraction of cholesterol-fed rats; diosgenin had no effect on serum cholesterol in normocholesterolemic rats. In contrast to cholestyramine, diosgenin markedly increased neutral sterol excretion without altering bile acid excretion; in vitro, diosgenin had no effect on bile acid binding. Diosgenin treatment increased hepatic and intestinal cholesterol synthesis as well as the activity of hepatic HMG CoA reductase. This was accompanied by increased biliary concentration of cholesterol, but not of bile acids. Diosgenin had no effect on cholesterol synthesis when added to normal rat liver homogenates. It was concluded that diosgenin interferes with the absorption of cholesterol of both exogenous and endogenous origin; such interference is accompanied by derepressed, i.e., increased, rates of hepatic and intestinal cholesterol synthesis. The increased unabsorbed cholesterol together with enhanced secretion of cholesterol into bile resulted in increased excretion of neutral sterols without affecting the biliary and fecal excretion of bile acids.     

l-Alanine-α-Ketobutyrate Aminotransferase of Pseudomonas sp.

Modified fungal product 4-O-methylascochlorin (MAC) is an experimental agent affecting lipid and carbohydrate metabolism in mammals. The hypocholesterolemic properties of MAC were studied using rats fed on a standard laboratory diet. Because of the insolubility in water, reproducibility of the hypocholesterolemic activity had usually been poor for rats fed ad libitum. The difficulty was overcome by controlled reverse-phase feeding; MAC significantly lowered serum total cholesterol (s-TC) in rats only when given by gastric intubation soon after diet intake.

MAC increased fecal excretion of neutral and acidic sterols and also increased biliary flow accompanying increments in biliary cholesterol, bile acids and phospholipids. A much larger increase in neutral sterols was characteristic for MAC. However, intestinal absorption of cholesterol and cholic acid was unaffected by MAC. Three mechanisms therefore seemed to be working in hypocholesterolemic activity: (a) withdrawal of hepatic cholesterol into bile, (b) a larger fecal loss of sterols following increment of biliary sterols and (c) enhanced bile acid synthesis compensating the larger fecal loss. A negative sterol balance often leads to an increase in hepatic cholesterogenesis. However, cholesterogenesis, as judged from incorporation of the precursors, was unchanged by MAC.     

Mechanism of action of antiatherogenic and related effects of Ficus bengalensis Linn. flavonoids in experimental animals

One month treatment of alloxan diabetic dogs with a glycoside, viz. leucopelargonin derivative (100 mg/kg/day) isolated from the bark of F. bengalensis decreased fasting blood sugar and glycosylated haemoglobin by 34% and 28% respectively. Body weight was maintained in both the treated groups while the same was decreased significantly by 10% in the control group. In cholesterol diet fed rats, as the atherogenic index and the hepatic bile acid level and the faecal excretion of bile acids and neutral sterols increased, the HMGCoA reductase and lipogenic enzyme activities in liver and lipoprotien lipase activity in heart and adipose tissue and plasma LCAT activity and the incorporation of labelled acetate into free and ester cholesterol in liver decreased significantly. On treatment with the two ficus flavonoids, viz. leucopelargonin and leucocyanin derivatives and another flavonoid quercetin (100 mg/kg/day) the above said effects except on bile acids and sterols and lipogenic enzymes were significantly reversed in the cholesterol fed rats. However in the treated rats the hepatic level of bile acids and the faecal excretion of bile acids and neutral sterols still further increased and the action of lipogenic enzyme glucose 6 phosphate dehydrogenase was still further decreased. These effects of leucopelargonidin and quercetin were better than that of the second. Toxicity studies are required to be carried out to find out if the ficus flavonoids could be used as health promoters as they are hypocholesterolemic and antioxidant in action.     

Cholesterol gallstones in alloxan-diabetic mice

Normal and alloxan-diabetic male mice (Crj-ICR) were fed a diet containing 0.5% cholesterol for 5 and 10 weeks, and gallbladder bile was analyzed for cholesterol, phospholipids and bile acids, feces for sterols and bile acids, and plasma and liver for cholesterol, phospholipids, and triglycerides. Normal mice developed no gallstones but the diabetic mice developed cholesterol gallstones with an incidence of 70% by 5 weeks and 80% by 10 weeks after feeding of the cholesterol diet. Diabetic mice fed the ordinary diet also developed stones (23%) by 10 weeks. In the diabetic mice, the gallbladder was enlarged about threefold, and biliary lipid concentration, diet intake, and fecal excretion of sterols and bile acids increased but body weight decreased. Cholic acid and beta-muricholic acid comprised over 40% each of the total biliary bile acids in normal mice, but cholic acid increased to about 80% and beta-muricholic acid decreased to a few percent in the diabetic mice. Fecal excretion of bile acids increased after cholesterol feeding in both normal and diabetic mice, but the increased bile acid in the normal animals was beta-muricholic acid and that in the diabetic mice was deoxycholic acid. The mice that developed gallstones showed a marked increase in biliary cholesterol value and decreases in gallbladder bile and bile acid concentration, but no difference in biliary and fecal bile acid composition, bile acid synthesis, fecal sterols, or plasma and liver lipid levels. Cholesterol absorption was increased in the diabetic mice when examined by plasma 14C/3H ratio and fecal 14C-labeled sterol excretion after a single oral administration of [14C]cholesterol and a simultaneous intravenous injection of [3H]cholesterol. These data led to the conclusion that cholesterol gallstones developed in alloxan-diabetic mice fed excess cholesterol, due to the hyperphagia and the enhancement of cholesterol absorption caused by increases in the synthesis and secretion of cholic acid.     

Intestinal steroids in rats are influenced by the structural parameters of pectin

We investigated the effects of pectin with different degrees of methylation (34.5, 70.8, and 92.6%, respectively) on the composition and concentration of intestinal and fecal bile acids and neutral sterols in conventional and germfree rats. Diets containing 6.5% pectin (galacturonan) were given for 3 weeks. High concentrations of free and secondary bile acids appeared in cecum and colon of conventional rats. With increasing degree of methylation, more bile acids were transported into lower parts of intestinal tract and excreted whereas the proportion of secondary bile acids decreased. In contrast, the composition of bile acids in intestinal contents and feces was relatively unchanged in germfree rats. Exclusively cholesterol was found as a neutral sterol in germfree rats. Coprostanol appeared in cecum of conventional rats and additionally coprostanone in colon. Amounts of neutral sterols increased with increasing degree of methylation of pectin. Additionally, concentrations of bile acids in plasma decreased if the pectin-containing diets were given. Besides the degree of methylation, the molecular weight of pectin used in the diets influenced concentration and composition of intestinal and fecal steroids in rats.     

Soyasaponins lowered plasma cholesterol and increased fecal bile acids in female golden Syrian hamsters

A study was conducted in hamsters to determine if group B soyasaponins improve plasma cholesterol status by increasing the excretion of fecal bile acids and neutral sterols, to identify group B soyasaponin metabolites, and to investigate the relationship between a fecal group B soyasaponin metabolite and plasma lipids. Twenty female golden Syrian hamsters, 11-12 weeks old and 85-125 g, were randomly assigned to a control diet or a similar diet containing group B soyasaponins (containing no isoflavones), 2.2 mmol/kg, for 4 weeks. Hamsters fed group B soyasaponins had significantly lower plasma total cholesterol (by 20%), non-high-density lipoprotein (HDL) cholesterol (by 33%), and triglycerides (by 18%) compared with those fed casein (P < 0.05). The ratio of total cholesterol to HDL cholesterol was significantly lower (by 13%) in hamsters fed group B soyasaponins than in those fed casein (P < 0.05). The excretion of fecal bile acids and neutral sterols was significantly greater (by 105% and 85%, respectively) in soyasaponin-fed hamsters compared with those fed casein (P < 0.05). Compared with casein, group B soyasaponins lowered plasma total cholesterol levels and non-HDL cholesterol levels by a mechanism involving greater excretion of fecal bile acids and neutral sterols. Hamsters fed group B soyasaponins statistically clustered into two fecal soyasaponin metabolite-excretion phenotypes: high excreters (n = 3) and low excreters (n = 7). When high and low producers of this soyasaponin metabolite were compared for plasma cholesterol status, the high producers showed a significantly lower total-cholesterol-to-HDL-cholesterol ratio compared with the low producers (1.38 +/- 0.7 vs. 1.59 +/- 0.13; P < 0.03). Greater production of group B soyasaponin metabolite in hamsters was associated with better plasma cholesterol status, suggesting that gut microbial variation in soyasaponin metabolism may influence the health effects of group B soyasaponins.     

Increase of bile acids synthesis and excretion caused by taurine administration prevents the ovariectomy-induced increase in cholesterol concentrations in the serum low-density lipoprotein fraction of Wistar rats

We examined the effect of dietary taurine on the concentrations of serum cholesterol and apolipoprotein in lipoprotein fractions of Six-month-old ovariectomized, which were used as a model of hypercholesterolemia in postmenopausal woman, or sham operated rats. Taurine significantly reduced the serum total and low-density lipoprotein cholesterol concentrations only in the ovariectomized rats. In contrast, taurine significantly lowered the serum apolipoprotein B concentration and serum very low-density lipoprotein-apolipoprotein E concentration only in the sham operated rats. The serum total and high density lipoprotein-apolipoprotein E concentrations were significantly lower in the rats fed taurine than in those fed the control diet regardless of whether they had undergone ovariectomy. The esterified cholesterol level in the liver was significantly lower and the level of hepatic cholesterol 7 alpha-hydroxylase activity was significantly higher in the rats fed taurine than in those fed the control diet. The total bile acids concentration in the feces and intestinal contents of rats fed taurine were significantly higher than those in rats fed the control diet regardless of whether they had undergone ovariectomy. In the sham-rats, taurine accelerated bile acid synthesis and excretion, thereby increasing cholesterol consumption. The increased cholesterol consumption might be compensated by accelerating cholesterol synthesis and/or reducing the synthesis and release of very low-density lipoprotein from the liver. But in the ovariectomized rats, although taurine also accelerated bile acid synthesis and excretion, cholesterol demand might be compensated by excess cholesterol in the blood.     

Alteration of biliary ursodeoxycholic acid in guinea pig during early stages of cholestyramine feeding

The effects of cholestyramine feeding on biliary ursodeoxycholic acid, fecal excretion of bile acids and neutral sterols on cholesterol 7α-hydroxylase and hepatic HMG-CoA reductase were examined in the guinea pig. In the bile there was a 57% decrease in the concentration of ursodeoxycholic acid while an increase was observed in the concentration of chenodeoxycholic acid. Cholestyramine feeding for ten days resulted in a decrease in plasma cholesterol levels and an increase in both hepatic HMG-CoA reductase and cholesterol 7α-hydroxylase activities. The fecal excretion of both bile acids and neutral sterols was significantly increased.     

Hypocholesterolemic effect of anhydrous milk fat ghee is mediated by increasing the secretion of biliary lipids

The anhydrous milk fat ghee is one of the important sources of fat in the Indian diet. Our earlier studies showed that rats fed diets containing greater than 2.5 wt% of ghee had lower levels of serum cholesterol compared with rats fed diets containing groundnut oil. To evaluate the mechanism of the hypocholesterolemic effect of ghee, male Wistar rats were fed a diet containing 2.5 or 5.0 wt% ghee for a period of 8 weeks. The diets were made isocaloric with groundnut oil. Both native and ghee heated at 120 degrees C containing oxidized lipids were included in the diet. The ghee in the diet did not affect the 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase activity in the liver microsomes, but it significantly increased biliary excretion of cholesterol, bile acids, uronic acid, and phospholipids. The rats fed ghee had lower levels of cholesterol esters in the serum as well as in the intestinal mucosa. Both native and oxidized ghee influenced cholesterol metabolism. These results indicate that supplementation of diets with ghee lipids would increase the excretion of bile constituents and lower serum cholesterol levels.     

Medium-Chain Fatty Acids Enhanced the Excretion of Fecal Cholesterol and Cholic Acid in C57BL/6J Mice Fed a Cholesterol-Rich Diet

The objective of the present study was to investigate the cholesterol-reducing effect of medium-chain fatty acids (MCFAs) completed by elevated excretion of fecal neutral steroids and/or bile acids. Blood and liver lipid profiles, fecal neutral steroids, bile acids, and mRNA and protein expression of the genes relevant to cholesterol homeostasis were measured and analyzed in C57BL/6J mice fed a cholesterol-rich diet with 2% caprylic acid or capric acid for 12 weeks. Blood total cholesterol and low-density lipoprotein cholesterol (LDL-c) levels were reduced significantly as compared to diet with palmitic acid or stearic acid. Caprylic acid promoted the excretion of fecal neutral steroids, especially cholesterol. The excretion of fecal bile acids, mainly in the form of cholic acid was enhanced and accompanied by elevated expression of mRNA and the protein of hepatic cholesterol 7α-hydroxylase (CYP7A1). These results indicate that MCFAs can reduce blood cholesterol by promoting the excretion of fecal cholesterol and cholic acid.     

Dietary taurine enhances cholesterol degradation and reduces serum and liver cholesterol concentrations in rats fed a high-cholesterol diet

Summary.  The effect of taurine on hypercholesterolemia induced by feeding a high-cholesterol (HC) diet (10 g/kg) to rats was examined. When taurine was supplemented to HC for 2 wk, serum total cholesterol significantly decreased and serum HDL-cholesterol increased compared with the HC diet group. In the hypercholesterolemic rats fed the HC diet, the excretion of fecal bile acids and hepatic cholesterol 7α-hydroxylase (CYP7A1) activity and its mRNA level increased significantly, and the supplementation of taurine further enhanced these indexes, indicating an increase in cholesterol degradation. Agarose gel electrophoresis revealed that, in hypercholesterolemic rats fed the HC diet, the serum level of the heavier VLDL increased significantly, but taurine repressed this increase and normalized this pattern. Significant correlations were observed between the time-dependent increase of CYP7A1 gene expression and the decrease of blood cholesterol concentration in rats fed the HC diet supplemented with taurine. These results suggest that the hypocholesterolemic effects of taurine observed in the hypocholesterolemic rats fed the HC diet were mainly due to the enhancement of cholesterol degradation and the excretion of bile acid. Received December 4, 2001 Accepted January 2, 2002 Published online September 10, 2002 Acknowledgment This work was supported by a grant of Taisho Pharmaceutical Co., Ltd (Japan). We thank J. I. Gordon for their generous gifts of cDNAs. Authors' address: Dr. Hidehiko Yokogoshi, School of Food and Nutritional Sciences, The University of Shizuoka, Shizuoka 4228526, Japan, E-mail: yokogosi@u-shizuoka-ken.ac.jp     

The effect of high-amylose cornstarch on lipid metabolism in OVX rats is affected by fructose feeding

We examined whether the effects of high-amylose cornstarch (HACS) on lipid metabolism in ovariectomized (OVX) rats were affected by high-fructose feeding. Sucrose (482 g/kg diet) was used as fructose source. OVX rats were fed one of the following four diets for 21 days: a sucrose-based or cornstarch-based cholesterol-free diet with or without HACS (150 g/kg diet). Body weight and food intake were increased by sucrose. Plasma total cholesterol and low-density lipoprotein cholesterol concentrations were increased by sucrose and decreased by HACS in cornstarch-fed rats, but not in sucrose-fed rats. Liver total lipids and concentrations of plasma and liver triacylglycerol (TAG) were increased by sucrose, whereas plasma TAG concentration was decreased by HACS, in sucrose-fed rats. However, liver cholesterol concentration was not affected by diet. The amount of cholesterol in small-intestinal contents was increased in sucrose-fed rats, but not in cornstarch-fed rats, but that of bile acids was not affected by diet. Fecal excretions of bile acids and neutral sterols were increased by HACS. The level of sterol-regulatory element-binding protein-1c mRNA was increased by sucrose and decreased by HACS in sucrose-fed rats, but not in cornstarch-fed rats. The level of farnesoid X receptor mRNA was decreased by sucrose and increased by HACS in cornstarch-fed rats, but not in sucrose-fed rats, as was the level of cholesterol 7α-hydroxylase mRNA. These results show that the effect of HACS on hyperlipidemia induced by ovarian hormone deficiency would be affected by the consumption of fructose-rich sweeteners such as sucrose and high-fructose syrup.     

Sources of error in the isotopic cholesterol balance method in African green monkeys consuming a cholesterol-free diet

Six African green monkeys were labeled intravenously with [1,2-(3)H]cholesterol while consuming a cholesterol-free liquid formula diet. The plasma cholesterol specific activity was compared with the specific activity of the biliary cholesterol and bile acids and with the fecal neutral steroids in order to determine whether the traditional isotopic balance method was valid for the calculation of endogenous cholesterol excretion. The specific activity of biliary cholesterol and bile acids averaged 10-15% lower than plasma cholesterol specific activity. Fecal cholesterol and coprostanone specific activities were similar to that of the biliary cholesterol, but the specific activity of fecal coprostanol was approximately 25% lower. This suggests that biliary cholesterol and bile acids were derived from a pool of hepatic cholesterol that did not completely equilibrate with the whole body exchangeable cholesterol pool. In addition, there was further reduction in the specific activity of coprostanol, the major fecal neutral steroid, presumably by cholesterol synthesized in the lower intestine and preferentially converted to coprostanol. As a result, the traditional isotopic balance procedure underestimated endogenous neutral steroid excretion by 46% and bile acid excretion by 31% in African green monkeys fed the cholesterol-free diet. Within 7 days after the addition of 1 mg cholesterol/kcal to the diet, the specific activities of plasma and biliary cholesterol and biliary bile acids were identical and there was no difference in the specific activities of the individual fecal neutral steroids. Thus, the traditional isotopic balance procedure (DPM fecal neutral steroids + bile acids/specific activity [DPM/mg] plasma cholesterol) can be used for calculation of endogenous cholesterol excretion in cholesterol-fed animals during the nonsteady state when plasma cholesterol concentrations are rapidly increasing, as well as after a new steady state has been achieved.-Henderson, G. R., and R. W. St. Clair. Sources of error in the isotopic cholesterol balance method in African green monkeys consuming a cholesterol-free diet.     

Hypolipidemic principle of the inflorescence stalk of plantain (Musa sapientum)

A pectin present in the juice of the inflorescence stalk of plantain(Musa sapientum) has been isolated. The material contained 32.4% hexoses and 52.5% uronic acid. On administration to rats fed both cholesterol free and cholesterol diet, this material showed significant lowering of cholesterol and triglycerides in the serum, liver and aorta. There was decreased cholesterogenesis in the liver as was evident from decreased activity of hydroxymethylglutaryl coenzyme A reductase and decreased incorporation of labelled acetate into hepatic cholesterol. Hepatic bile acids showed significant increase and there was increased fecal excretion of neutral sterols and bile acids. Release of lipoproteins into the circulation was lower. The material also caused increase in the activity of lipoprotein lipase in the heart and adipose tissue and also of plasma lecithin: cholesterol acyl transferase     

Mechanism for the cholesterol-lowering action of egg white protein in rats

Eggs are a popular source of dietary cholesterol, but their consumption does not necessarily result in an increased serum cholesterol concentration. We investigated the cholesterol-lowering activity of egg white protein (EWP) and its potential mechanism in rats. The consumption of EWP resulted in a decreased concentration of cholesterol in the serum, liver and intestinal mucosa. The excretion of fecal neutral sterols and bile acids was greater by rats fed with EWP than by those fed with casein. The ratio of cholesterol and bile acids in the micellar phase to those in the solid phase was lower in the intestinal contents from rats fed with EWP than from those fed with casein. These results suggest that the cholesterol-lowering activity of EWP can be attributed to lowering the cholesterol absorption by intervening in the micellar formation in the intestines.     

Influence of experimental diets on cholesterol and triglyceride levels of rabbit blood serum lipoproteins

Groups of rabbits were fed for six weeks various diets: standard died + ethanol, high-cholesterol diet and a high-cholesterol + ethanol one. During the next six weeks every diet was supplemented with a fresh vegetable (carrot). Cholesterol and triglycerides were determined in the whole serum and in lipoprotein fractions. In rabbits fed standard diet ethanol caused a moderate elevation of VLDL cholesterol and triglyceride and LDL cholesterol levels. In animals on high-cholesterol diet cholesterol and triglyceride concentrations in these fractions were very high. Simultaneous consumption of large amounts of cholesterol and of ethanol resulted in a greater rise of cholesterol concentration in the whole serum and in VLDL and LDL fraction than did high-cholesterol diet alone. Addition of carrot caused a pronounced reduction of serum cholesterol concentration in animals fed all kinds of diets. The reduction concerned mainly VLDL.